Method for polishing organic film on semiconductor substrate by use of resin particles, and slurry

ABSTRACT

A method for polishing an organic film, comprising polishing an exposed organic film provided on a semiconductor substrate by use of slurry containing resin particles.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based upon and claims the benefit of priorityfrom the prior Japanese Patent Application No. 2002-290106, filed Oct.2, 2002, the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a method for polishing anorganic film, such as a resist or the like, on a semiconductorsubstrate, by use of resin particles, and slurry for use in thepolishing.

[0004] 2. Description of the Related Art

[0005] As conventional techniques, there is a tape-like polishing agentprepared by applying thermosetting resin particles and a binder onto afilm base material and then drying them (e.g., see page 3 of Jpn. Pat.Appln. KOKOKU Publication No. 2-51951), and there is known amicro-spherical polishing agent made of a melamine phenol polyimideresin, and a co-rubbing polishing method (e.g., see page 2 of Jpn. Pat.Appln. KOKAI Publication No. 2001-277105). In addition, there is amethod for subjecting to CMP treatment a resist surface cured by an ionbeam implantation or plasma etching (e.g., see page 1 and FIG. 4 of U.S.Pat. No. 6,235,636), and a chemical mechanical polishing of a resistwhich comprises pressing a polishing cloth against a wafer whilesupplying fuming nitric acid (e.g., see the abstract and FIG. 3 of Jpn.Pat. Appln. KOKAI Publication No. 11-87307).

[0006] Until now, a chemical mechanical polishing method (CMP method)has been used in which a slurry containing silica particles is used as apolishing material, in flattening a surface of a semiconductor waferhaving an uneven substrate on which fine slots and the like are formed,and a resist film deposited on the uneven substrate surface includinginner surface parts of the slots and the like.

[0007] Description will now be made of a manufacturing method of acapacitor by use of the CMP method utilizing silica particles.

[0008] First, FIGS. 6A to 6C are sectional views showing a capacitormanufacturing process (trench structure) according to a firstconventional example. Here, a region on a silicon substrate 61 in whichdeep and narrow slots DT (deep trench) are formed is referred to as acell array section 6 a, and a region in which no slots DT are formed isreferred to as a field section 6 b.

[0009] As shown in FIG. 6A, the slots DT are formed in the siliconsubstrate 61 by using, e.g., an RIE technique. An ASG film 62 is formedon inner surfaces of the slots DT, and a resist film 63 is formed to apredetermined thickness to completely fill the slots DT. Accordingly, asurface of the resist film 63 in the cell array section 6 a is lowerthan that in the field section 6 b with respect to a flat surfaceindicated by a broken line, whereby a step is formed on the surface ofthe resist film 63.

[0010] Afterward, the resist film 63 is etched back in order to leavethe resist film at a predetermined height from the slots DT. However,the etching-back step is a uniform etching operation carried out byusing the surface of the resist film 63 as a reference, and therefore,it is impossible to form a resist film having a uniform height from thebottoms of the slots DT. As shown in FIG. 6B, resist films 631 to 636having a nonuniform thickness on which the step shape of the resist filmsurface is reflected are formed in the respective slots DT.

[0011] Subsequently, the resist films 631 to 636 left in the respectiveslots DT are used as masks to etch the ASG film 62 not covered with theresist films 631 to 636, and then, the resist films 631 to 636 areetched off. Accordingly, heights of the resist films 631 to 636 arepatterned in the ASG film 62 formed in the slots DT, whereby ASG films(not shown) having a nonuniform height are formed in the respectiveslots DT.

[0012] Then, an unillustrated tetraethoxy silane film (TEOS film) isformed on the silicon substrate 61 including inner surface parts of theslots DT, and a heat treatment is carried out to inject an impurity Ascontained in the ASG film into the silicon substrate 61, whereby an Asdiffused region 66 is formed. Thus, the As diffused region 66, in whichheights in the slots DT are nonuniform, is formed as a common electrodeof capacitors in the silicon substrate 61.

[0013] Afterward, the TEOS film and the ASG film are removed to form anitric oxide film (NO film) 67 on the substrate, which includes theinner surface parts of the slots DT, whereby a capacitor insulating filmis formed. Further, polysilicon is deposited to fill the slots DT.

[0014] Subsequently, the polysilicon is flattened to be on the sameplane as a surface of the NO film 67, and other electrodes 681 to 686are formed in the slots DT. Accordingly, capacitors as shown in FIG. 6Care formed.

[0015] The height of the As diffused region 66, which is the commonelectrode of the capacitors, is not uniform, and opposing areas of theAs diffused region 66 and the NO film 67, which is a capacitorinsulating film, are not uniform. Consequently, uniformity of opposingareas of electrodes for each capacitor cannot be secured, wherebycapacitors having nonuniform capacity values are formed.

[0016] In order to deal with the formation of such nonuniformcapacitors, the slots DT may be formed deeper to secure a minimumcapacity sufficient for a semiconductor device. However, the formationof the deeper trenches DT may impose a performance/control load on adevice manufacturing process, consequently causing a problem ofimpossibility of manufacturing a device of expected performance.

[0017]FIGS. 7A to 7D are sectional views showing a capacitormanufacturing process (trench structure) according to a secondconventional example.

[0018] As shown in FIG. 7A, the plurality of slots DT are formed in asilicon substrate 61.

[0019] An ASG film 62 is formed on inner wall surfaces of the respectiveslots DT, and a resist film 63 is also formed. Accordingly, a surface ofthe resist film 63 in a cell array section 6 a is lower than that in afield section 6 b with respect to a flat surface indicated by a brokenline, and a step is formed on the surface of the resist film 63.

[0020] Then, a known CMP method is used to polish the resist film 63.However, because of hard silica particles, polishing is carried out tothe ASG film 62 below the resist film 63. Consequently, an erosion 71 ora scratch 72 shown in FIG. 7B occurs. In addition, the formation of theslots DT in the substrate 61 causes clogging 73, where openings of theslots DT are clogged with silica particles.

[0021] Then, as shown in FIG. 7C, resist films 741 to 746 are etchedback. However, clogging of the opening with silica particles preventsetching-back of the resist film 743. Consequently, the height of theresist film 743 is not uniform with those of resist films 771 to 775.

[0022] Subsequently, each of the resist films 771 to 775, and the resistfilm 743 are used as masks to etch the ASG film 62. Then, the resistfilms 771 to 775, and the resist film 743 are etched off. Accordingly,heights of the resist films 771 to 775 and the resist film 743 arepatterned in the ASG film 62 formed in the slots DT, whereby ASG films(not shown) having a nonuniform height are formed in the slots DT.

[0023] Then, an unillustrated tetraethoxy silane film (TEOS film) isformed on the substrate, which includes inner surface parts of the slotsDT, and a heat treatment is carried out to inject an impurity containedin the ASG film into the silicon substrate 61, whereby an As diffusedregion 75 is formed. Thus, the nonuniform As diffused region 75 isformed as a common electrode of capacitors in the silicon substrate 61.

[0024] Then, the TEOS film and the ASG film are removed to form a nitricoxide film (NO film) 67 on the substrate, which includes the innersurface parts of the slots DT, whereby a capacitor insulating film isformed. Further, polysilicon is deposited on the substrate 61 includingthe inner side of the slots DT. Then, the polysilicon is etched to beflattened on the surface of the NO film 67, thereby forming otherelectrodes 761 to 766. Accordingly, capacitors as shown in FIG. 7D areformed.

[0025] The height of the As diffused region 66 in the slots DT, which isthe common electrode of the capacitors, is not uniform, and opposingareas of the As diffused region 66 and the NO film 67, which is acapacitor insulating film, are not uniform. Consequently, equal opposingareas of electrodes for capacitors cannot be secured, thus capacitorshaving nonuniform capacity values are formed. Therefore, theabove-described problem occurs.

[0026]FIGS. 8A to 8C are sectional views showing a capacitormanufacturing process (stack structure) according to a thirdconventional example.

[0027] As shown in FIG. 8A, on a substrate 81, an insulating film 82 isformed flat to a predetermined thickness, and slots SN (storage node)are formed by using an RIE technique. A polysilicon film 83 is formed tobe uniform in thickness on a surface of the insulating film 82, whichincludes inner surface parts of the slots SN, and a resist film 84 isformed to a predetermined thickness to fill the slots SN.

[0028] Then, silica particles are used to polish upper parts of theresist film 84 and the polysilicon film 83 by a CMP method, wherebyresist masks 841 to 845 are formed. Consequently, an erosion 85 or ascratch 86 shown in FIG. 8B occurs. In addition, an opening of a slot SNis clogged with silica particles, which form a clogging 87.

[0029] Then, the resist masks 841 to 845 are etched off. However,because of the clogging 87 at the opening of the slot SN, the resistmask 843 is left unetched. Then, the insulating film 82 is etched tosimultaneously remove the clogging 87. However, the resist mask 843 maystill remains.

[0030] Subsequently, a nitric oxide film (NO film) 89 is formed onpolysilicon electrodes 831 to 835 and the substrate 61 to form acapacitor insulating film 89. Then, a polysilicon electrode 88 is formedon the NO film 89 to form an opposite common electrode of capacitors.

[0031] Accordingly, because of the electrodes, opposing areas of whichare nonuniform, the capacitors have nonuniform capacity values. Inaddition, the resist mask 843 is left unetched. Consequently, thissection has lost its function as a capacitor.

[0032] Furthermore, in order to deal with the formation of suchnonuniform capacity values, the slots SN may be formed higher to securea minimum capacity sufficient for a semiconductor device. However, theformation of the higher slots SN may impose a performance/control loadon a device manufacturing process, consequently causing a problem ofimpossibility of manufacturing a semiconductor device of expectedperformance.

BRIEF SUMMARY OF THE INVENTION

[0033] An aspect of the present invention provided a method forpolishing an organic film, comprising polishing a semiconductorsubstrate having an exposed organic film by use of a slurry containingresin particles.

[0034] Furthermore, another aspect of the present invention provides aslurry for chemical mechanical polishing, which is a suspension preparedby dispersing resin particles in a liquid having a chemical polishingfunction for an organic film.

[0035] According to the polishing by use of the slurry of the foregoingconstitution, the organic film is polished without damaging a foundationlayer of the organic film which is a polishing target, whereby itssurface can be flattened in a good condition. For example, the slurrycan be used for a manufacturing process of a semiconductor device toimprove the manufacturing yield.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0036]FIGS. 1A to 1C are sectional views showing a capacitor formingprocess according to a first embodiment of the present invention.

[0037]FIGS. 2A to 2D are sectional views showing a sequel to thecapacitor forming process of FIGS. 1A to 1C according to the firstembodiment of the invention.

[0038]FIGS. 3A to 3D are sectional views showing a sequel to thecapacitor forming process of FIGS. 2A to 2D according to the firstembodiment of the invention.

[0039]FIGS. 4A to 4D are sectional views showing a capacitor formingprocess according to a second embodiment of the present invention.

[0040]FIGS. 5A to 5C are sectional views showing a sequel to thecapacitor forming process of FIGS. 4A to 4D according to the secondembodiment of the invention.

[0041]FIGS. 6A to 6C are sectional views showing a capacitor formingprocess according to a first conventional example.

[0042]FIGS. 7A to 7D are sectional views showing a capacitor formingprocess according to a second conventional example.

[0043]FIGS. 8A to 8C are sectional views showing a capacitor formingprocess according to a third conventional example.

DETAILED DESCRIPTION OF THE INVENTION

[0044] Next, detailed description will be made of the embodiments of thepresent invention with reference to the accompanying drawings.

[0045]FIGS. 1A to 3D are sectional views showing a capacitor (trenchstructure) forming process according to a first embodiment of thepresent invention. As shown in FIG. 1A, predetermined patterns forcapacitor formation are formed on a surface of a silicon substrate 11 toform, e.g., memory cells of a DRAM. Based on these patterns, a pluralityof deep and narrow slots DT are formed to be uniform in size inpredetermined parts of the silicon substrate 11 by using, e.g., areactive ion etching (RIE) technique. In this case, a region in whichthe slots DT are formed is set as a cell array section 1 a, and a regionin which no slots DT are formed is set as a field section 1 b.

[0046] Then, an Arseno Silicate Glass (referred to as ASG, hereinafter)film 12 is formed to be uniform in thickness on a surface of the siliconsubstrate 11, which includes inner surface parts of the slots DT, byusing, e.g., chemical vapor deposition (CVD). In addition, a resist film13, which is an organic film of a predetermined thickness, is formed onthe ASG film 12 to completely fill the slots DT.

[0047] A part of the resist film 13 is absorbed in the slots DT in thecell array section 1 a. Accordingly, on the surface of the siliconsubstrate 11, the height of the surface of the resist film 13 is lowerin the cell array section 1 a than that in the field section 1 b.Consequently, a step indicated by a solid line is formed on the surfaceof the resist film 13 with respect to a flat surface indicated by abroken line.

[0048] Then, as shown in FIG. 1B, an imaginary line 1 c is drawn on asurface of the ASG film 12 formed on the substrate 11 to extend from thecell array section 1 a to the field section 1 b. The resist film 13 ispolished to this line by use of a CMP device and slurry containing resinparticles, so that it is flattened. A CMP device is one with a polishingpad fixed to a rotary surface plate, a nozzle for supplying slurry ontothe polishing pad, a wafer holding section rotated in a directionopposite that of the rotary surface plate, and a drive unit foroperating these components. A wafer or the silicon substrate 11 is fixedby the wafer holding section, the slurry is injected between the waferand the polishing pad, and the CMP device is driven by the drive unit,whereby a wafer surface is polished.

[0049] The resin particles contained in the slurry has a particle sizelarger than a minimum opening size 1 d of a residual opening of the slotDT formed immediately after the forming step of the ASG film 12.Accordingly, in polishing by CMP, the resin particles almost never enterbelow the imaginary line 1 c to drill through the resist in the slotsDT. Thus, clogging of the opening with the resin particles almost neveroccurs.

[0050] However, if resin particles are smaller than the above-describedparticle size, or fragmented, the slots DT may be clogged with the resinparticles in the CMP process. On the other hand, the resin particles areunresistant to etching for removing the resist 13. Thus, even if theslots DT are clogged with the resin particles smaller than thepredetermined particle size or the fragments of the resin particles inthe CMP process, in subsequent etching of resist masks 141 to 146, theresin particles are removed together with the resist masks.

[0051] Further, preferably, the resin particles are spherical and are ofuniform size. It was found that formation of resin particles by using apolystyrene resin facilitated control of particle size to improveuniformity. Uniformly-sized particles can also improve dispersion of theresin particles in the slurry. Because of the uniform particle size, awafer surface and a polishing pad surface can be maintained parallel,while they are rotated relatively to each other, whereby the surface ofthe wafer is uniformly polished.

[0052] The ASG film 12 is harder than the resin particles contained inthe slurry, and the resin particles are harder than the resist film 13.Accordingly, since the ASG film 12 operates as a stopper film for CMP,only the resist film 13 softer than the resin particles contained in theslurry is polished. Thus, scratches or erosions of the resist film 13can be surely prevented.

[0053] Furthermore, when the slurry was formed, an additive containing,as a component, an organic nitrogen compound having an amine group orthe like was added, whereby an etching rate was improved, and theuniformity of the slurry in the polished surface was also improved. Inaddition, because of small volatility of the additive, good liquidstability of the slurry was verified.

[0054] The ASG film 12 is not polished by the slurry containing theresin particles. Accordingly, the patterns for the capacity formed onthe surface of the silicon substrate 11 are protected by the ASG film12.

[0055] Therefore, as shown in FIG. 1B, by the CMP method in which theslurry containing the resin particles is used, the resist film 13 isregulated by the surface of the ASG film 12 to be polished, andflattened well in a position of the imaginary line 1 c. Thus, thesurfaces of the resist masks 141 to 146 in the slots DT are flattened,whereby the resist masks 141 to 146 are formed to be uniform in heightin the slots DT.

[0056] Then, as shown in FIG. 1C, in order to leave a resist mask of apredetermined height from bottoms in the slots DT, each of the resistmasks 141 to 146 are etched back by using the imaginary line 1 c as areference. Accordingly, as shown in the sectional view of FIG. 1C,resist masks 151 to 156 are formed, which have equal heights from thebottoms of the slots DT to an imaginary line 1 e which is parallel withthe imaginary line 1 c.

[0057] Though not shown, even if resin particles smaller than thepredetermined particle size, or fragments of the resin particles areclogged in the slots DT during the CMP process of FIG. 1B, the resinparticles or the fragments clogged in the slots DT are removed togetherwith the resist masks 141 to 146 in the current etching step. Thus, insubsequent steps, the resin particles causing clogging have no adverseeffects.

[0058] Here, FIG. 2A shows a sequel to the capacitor forming processshown in FIG. 1C. As shown in FIG. 2A, the resist masks 151 to 156 areused as etching masks, and a part of the exposed ASG film 12 is removedby wet etching, which uses a hydrofluoric-based etching liquid.Accordingly, ASG films 161 to 166 are remained in the slots DT to beuniform in height.

[0059] Then, the resist masks 151 to 156 are etched to leave ASG films161 to 166 having uniform heights from the bottoms in the slots DT, asshown in FIG. 2B.

[0060] Then, as shown in FIG. 2C, tetraethoxy silane (TEOS) gas is usedto form a thin TEOS film 17 uniform in thickness on the surface of thesilicon substrate 11, the exposed inner surfaces of the slots DT and theASG films 161 to 166 by using plasma CVD. Subsequently, the TEOS film 17is used as a heat-treating film of the silicon substrate 11 to perform aheat treatment, whereby impurities As contained in the ASG films 161 to166 are diffused in the silicon substrate 11.

[0061] Therefore, as shown in FIG. 2D, an As diffused region 18 having acontact area equal to that of each slot DT is formed as a commonelectrode for the capacitors in the silicon substrate 11. In this case,diffusion time is set at least to join diffused regions extended fromthe inner wall surfaces of the slots DT adjacent to each other in thesilicon substrate 11 as shown in FIG. 2D.

[0062]FIG. 3A shows a sequel to the capacitor forming process of FIG.2D, where the TEOS film 17 and the heat-treated ASG films 161 to 166 areetched to be removed.

[0063] Then, as shown in FIG. 3B, for example, CVD is used to form anitric oxide (NO) film 19 to a uniform thickness as a capacitorinsulating film on a surface of the silicon substrate 11, which includesinner surface parts of the exposed slots DT.

[0064] Further, as shown in FIG. 3C, on the NO film 19, a polysiliconfilm 20 is formed to fill the slots DT.

[0065] Then, as shown in FIG. 3D, the polysilicon film 20 is etched toan imaginary line 1 f on an upper surface of the NO film 19 set inparallel with the imaginary line 1 e. Accordingly, in the slots DT,other electrodes 201 to 206 for the capacitors are formed to beinsulated from one another by the NO film 19.

[0066] As described above, according to the embodiment, the diffusedregions uniform in height can be formed along the inner wall surfaces ofthe slots DT in the silicon substrate 11. Thus, a plurality of diffusionareas having uniform areas for the respective electrodes of thecapacitors are formed around the slots DT in the silicon substrate 11,whereby capacities are also set to be uniform among the capacitors.

[0067] Therefore, the foregoing conventional problem causing theformation of nonuniform capacitors is solved, thereby reducing the loadon the process.

[0068] Furthermore, even if resin particles smaller than thepredetermined particle size, or fragments of resin particles are cloggedin the slots DT during the CMP process, the resin particles may beremoved together with the resist remained in the slots DT, since theresin particles are unresistant to etching of the resist film.

[0069] The particle size of the resin particles is easily controlled.Thus, the particle size is adjusted to be larger than the opening sizeid of the slots DT, in which the ASG film 12 shown in FIG. 1D is formed,whereby clogging can be prevented.

[0070] Furthermore, in the capacitor formed according to the embodiment,as shown in FIG. 3A, the diffused region 18 formed in the siliconsubstrate 11 is used as a common electrode of the capacitors. Inaddition, as described above, since the portions of the diffused region18 have uniform areas around the respective slots DT, it can be expectedthat capacitance of each capacitors are also uniform. Thus, for example,when the common electrode formed of the diffused region 18 is grounded,and when the other polysilicon electrodes 201 to 206 are connected tocell transistors of the DRAM memory device, the capacitors of thepresent embodiment may be used to form memory cells having goodcharacteristics.

[0071]FIGS. 4A to 5C are sectional views showing a capacitor (stackstructure) forming process according to a second embodiment of thepresent invention. As shown in FIG. 4A, an insulating film 42 is formedto a predetermined thickness on a substrate 41. Predetermined patternsfor capacitor formation are formed on a surface of the insulating film42 to form, e.g., a memory cell of a DRAM. A plurality of deep andnarrow slots SN are formed to be uniform in size in predetermined partsof the insulating film 42 by using, e.g., a reactive ion etching (RIE)technique. In this case, a region, in which the slots SN are formed, isset as a cell array section 4 a, and a region, in which no slots SN areformed, is set as a field section 4 b.

[0072] Then, a polysilicon film 43 is formed to be uniform in thicknesson a surface of the insulating film 42, which includes inner surfaceparts of the slots SN, by using, e.g., chemical vapor deposition (CVD).In addition, a resist film 44, which is an organic film of apredetermined thickness, is formed on the polysilicon film 43 tocompletely fill the slots SN. As in the case of FIG. 1A, since thedeposited resist is absorbed in the slots SN, a surface of the cellarray section 4 a of the resist film 44 is lower than that of the fieldsection 4 b to form a slope.

[0073] Then, as shown in FIG. 4B, an imaginary line 4 c is made on asurface of the polysilicon film 43 formed on the insulating film 42 toextend from the cell array section 4 a to the field section 4 b. Theresist film 44 is polished to this imaginary line 4 c to be flattened bya CMP device using slurry containing resin particles, whereby resistmasks 441 to 445 are formed in the slots SN.

[0074] Each of the resin particles contained in the slurry has aparticle size larger than at least a minimum opening size 4 d ofopenings of the slots SN formed immediately after the forming step ofthe polysilicon film 43. Accordingly, in polishing by CMP, the resinparticles almost never enter below the imaginary line 4 c to drillthrough the resin masks 441 to 445 in the slots SN. Thus, the cloggingof the openings of the slots SN with the resin particles almost neveroccurs.

[0075] However, if resin particles are smaller than the above-describedpredetermined particle size, or fragmented, the slots SN may be cloggedwith the resin particles in the CMP process. On the other hand, theresin particles are unresistant to etching for removing the resist masks441 to 445. Thus, even if the slots SN are clogged with the resinparticles smaller than the predetermined particle size or the fragmentsof the resin particles in the CMP process, in subsequent etching of theresist masks 441 to 445, the resin particles are removed together withthe resistmasks 441 to 445.

[0076] Further, preferably, the resin particles are spherical and havean uniform size. Therefore, in the embodiment of FIGS. 4A to 4D, thesurfaces of the substrate 41 or the surface of the insulating film 42and unillustrated polishing pad are maintained parallel while beingrotated relatively to each other, whereby a surface of a wafer isuniformly polished.

[0077] The polysilicon film 43 is harder than the resin particlescontained in slurry, and the resin particles are harder than the resist44. Accordingly, since the polysilicon film 43 operates as a stopperfilm for CMP in polishing of the resist 44, only the resist 44 softerthan the resin particles contained in the slurry is polished. Thus,scratches or erosions can be surely prevented.

[0078] Furthermore, the polysilicon film 43 is not polished or removedby the slurry containing the resin particles. Accordingly, the patternsof the insulating film 42 are protected by the polysilicon film 43.

[0079] Therefore, as shown in FIG. 4B, by the CMP method using theslurry containing the resin particles, the resist 44 is horizontallypolished to expose the surface of the polysilicon film 43, and flattenedon the imaginary line 4 c. Thus, the surfaces of the resist masks 441 to445 in the slots SN are flattened, whereby the resist masks 441 to 445are formed to be uniform in height in the slots SN.

[0080] Then, as shown in FIG. 4C, the resist masks 441 to 445 are usedas etching masks to etch the exposed portions of the polysilicon film43. Accordingly, polysilicon films 431 to 435 uniform in size are formedin the slots SN. In this case, the resist masks 441 to 445 haveresistance to etching for removing the exposed portions of thepolysilicon film 43. Thus, the resist film 44 on the polysilicon film 43is completely polished by the CMP method, whereby the polysiliconexposed parts can be selectively etched well.

[0081] Then, as shown in FIG. 4D, the resist masks 441 to 445 in theslots SN are removed by etching. Further, the insulating film 42 isremoved by etching.

[0082] Here, FIG. 5A shows a sequel to the capacitor forming processshown in FIG. 4D. As shown in FIG. 5A, polysilicon films 431 to 435U-shaped in section are formed as first electrodes 431 to 435 of thecapacitors on the substrate 41.

[0083] A nitric oxide (NO) film 45 is formed on the surfaces of thefirst electrodes 431 to 435, and the substrate 41. Thus, as shown inFIG. 5B, a capacitor insulating film is formed on the substrate 41 andthe first electrodes 431 to 435.

[0084] Then, a polysilicon film 46 is formed on the capacitor insulatingfilm 45 to fill the slot of the capacitor insulating film 45 formed ineach of the first electrodes 431 to 435. Accordingly, as shown in FIG.5C, the polysilicon film 46 is formed as a second or a common electrodeon the capacitor insulating film 45, thereby forming capacitors havingfirst electrodes 431 to 435 and second common electrode 46.

[0085] As described above, according to the second embodiment, heightsof the resist masks 441 to 445 in the slots SN are made uniform by theCMP using the resin particles to form the first electrodes 431 to 435 ofthe capacitors having uniform surface areas. Thus, the NO film 45 andthe polysilicon film 46 formed on the upper surfaces thereof are alsoformed to be uniform corresponding to the first electrodes 431 to 435.Therefore, capacitors having uniform capacities are formed on thesubstrate 41, and capacities are also set to be uniform among thecapacitors.

[0086] Therefore, the foregoing conventional problem caused theformation of nonuniform capacitors is solved to reduce the load on theprocess.

[0087] Furthermore, even if resin particles smaller than thepredetermined particle size, or fragments of resin particles, with whichthe slots SN have been clogged, are present in the CMP process, theresin particles are unresistant to etching of the resist film, andconsequently removed together with the resist film. Therefore, even ifthe slots SN are clogged with the resin particles smaller than thepredetermined particle size or fragments of the resin particles duringthe CMP, no resist film will be left in the slots SN until thecapacitors are completed. As a result, it is possible to preventformation of capacitors that will malfunction.

[0088] In addition, the particle size of the resin particles is easilycontrolled. Thus, the particle size is adjusted to be larger than theopening size 4 d of the slots SN, in which the polysilicon film 43 shownin FIG. 4D is formed, whereby clogging can be prevented.

[0089] Furthermore, in the capacitor formed according to the embodiment,as shown in FIG. 5C, the polysilicon film 46 formed on the uppermostsurface is integrated as the second electrodes of the capacitors, andcapacities of capacitors corresponding to the second electrodes 431 to435 are uniform. Thus, for example, the second electrode 46 is grounded,and the first electrodes 431 to 435 are connected to cell transistors ofa DRAM memory device, whereby memory cells having good characteristicscan be obtained.

[0090] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general invention concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. A method for polishing an organic film,comprising polishing a semiconductor substrate having an exposed organicfilm by use of slurry containing resin particles.
 2. The polishingmethod according to claim 1, wherein the organic film is a resist film.3. The polishing method according to claim 1, further comprisingchemically and mechanically polishing the organic film by use of theslurry containing the resin particles.
 4. The polishing method accordingto claim 2, further comprising chemically and mechanically polishing theorganic film by use of the slurry containing the resin particles.
 5. Thepolishing method according to claim 3, wherein the slurry containing theresin particles is a suspension prepared by dispersing the resinparticles in a liquid to be used for a chemical polishing of the organicfilm.
 6. The polishing method according to claim 4, wherein the slurrycontaining the resin particles is a suspension prepared by dispersingthe resin particles in a liquid to be used for a chemical polishing ofthe organic film.
 7. The polishing method according to claim 1, whereinthe organic film is formed on an uneven substrate including inner partsof a plurality of slots.
 8. The polishing method according to claim 2,wherein the organic film is formed on an uneven substrate includinginner parts of a plurality of slots.
 9. The polishing method accordingto claim 7, wherein the resin particles are unresistant to etching forremoving the organic film left in the inner parts of the plurality ofslots after the organic film formed on the substrate has been polishedto remove partially by use of the slurry.
 10. The polishing methodaccording to claim 8, wherein the resin particles are unresistant toetching for removing the organic film left in the inner parts of theplurality of slots after the organic film formed on the substrate hasbeen polished to remove partially by use of the slurry.
 11. Thepolishing method according to claim 7, wherein a particle size of theresin particles is larger than an opening size of the slots.
 12. Thepolishing method according to claim 8, wherein a particle size of theresin particles is larger than an opening size of the slots.
 13. Thepolishing method according to claim 5, wherein the resin particles arespherical particles comprising a polystyrene resin.
 14. The polishingmethod according to claim 6, wherein the resin particles are sphericalparticles comprising a polystyrene resin.
 15. The polishing methodaccording to claim 13, wherein the resin particles have a substantiallyuniform particle size.
 16. The polishing method according to claim 5,wherein the slurry containing the resin particles contains an organicnitrogen compound as an additive.
 17. The polishing method according toclaim 6, wherein the slurry containing the resin particles contains anorganic nitrogen compound as an additive.
 18. The polishing methodaccording to claim 7, wherein at least a surface of the substrate onwhich the organic film is formed is harder than the resin particles. 19.Slurry for chemical mechanical polishing, comprising a suspension liquidincluding a liquid for chemical polishing of an organic film and resinparticles dispersed in the liquid.
 20. The slurry according to claim 19,wherein the resin particles are spherical particles comprising apolystyrene resin.
 21. The slurry according to claim 19, wherein theslurry contains an organic nitrogen compound as an additive.
 22. Theslurry according to claim 19, wherein the resin particles have asubstantially uniform particle size.